The present invention relates to intumescent compositions based on foamed or unfoamed polyurethanes which contain a combination of polyester polyols, cyanuric acid derivatives and phosphorus-containing hydroxyl compounds as part of the formulation thereof and which are plastic and elastic in character.
Intumescent compositions are generally understood to be materials which foam under the influence of fire or heat and, in doing so, form an insulating and fire-resistant foam which protects the areas situated behind the foam against fire. Such intumescent compositions are generally known in the form of lacquers, coatings and mortars or cements.
Good intumescent compositions should be able to at least double in volume on contact with a flame and, in addition, should be unaffected by water. It would be of particular commercial interest if these properties could be combined with the absence of halogen, with a low density, with good thermal insulating properties in the absence of stressing, and with plasticity or flexibility and/or elasticity. Elastic-plastic intumescent compositions characterized by high dimensional stability could be widely used in the field of fire prevention in the form of semi-finished products, such as tapes, sheetings, profiles, coatings, granulates or fillings.
The use of melamine in the production of flexible foams using substantially linear polyols, and preferably polyether polyols, is known (see e.g. German Offenlegungsschrift No. 2,815,554). Although foams of this type are flame-resistant and do not burn completely on exposure to a flame, they do not have the character of intumescent compositions. In other words, they do not undergo any increase in volume on exposure to a flame, forming a fire-repellent foam.
According to an earlier proposal, flame-resistant sealing compounds free from phosphorus and halogen may be produced using branched polyesters containing hydroxyl groups. Sealing compounds of this type are not intumescent, i.e., they do not foam on exposure to a flame.
In yet another proposal optionally foamed intumescent compositions are obtained by reacting:
(1) polyisocyanates with PA1 (2) phosphorus-containing condensation products having at least one hydroxyl group obtainable by condensing (i) primary or secondary, aliphatic, cycloaliphatic, aromatic, araliphatic or heterocyclic monoamines and/or polyamines, which amino or polyamine may contain OH--groups, (ii) carbonyl compounds and (iii) dialkyl phosphites, optionally followed by alkoxylation, and PA1 (3) aromatic hydroxy carboxylic acids or salts thereof and PA1 (4) optionally water and/or other organic compounds containing isocyanate-reactive hydrogen atoms. PA1 (1) polyisocyanates with PA1 (2) phosphorus-containing condensation products having at least one hydroxyl group obtainable by condensing (i) primary or secondary aliphatic, cycloaliphatic, aromatic, araliphatic or heterocyclic monoamines and/or polyamines, which mono- or polyamines optionally may contain OH--groups; (ii) carbonyl compounds; and (iii) dialkyl phosphites, optionally followed by alkoxylation, and PA1 (3) polyesters containing hydroxyl groups and having an OH--number of from 140 to 300, obtained by reacting polycarboxylic acids containing from 2 to 10 carbon atoms with at least two polyols selected from two different groups of the following three: PA1 (4) cyanuric acid and/or cyanuric acid derivatives and PA1 (5) optionally water and/or other organic compounds containing isocyanate-reactive hydrogen atoms. PA1 R represents C.sub.1 -C.sub.8 alkyl or C.sub.1 -C.sub.8 hydroxyalkyl; and PA1 X represents H or methyl. PA1 n=2-4, preferably 2; and PA1 Q represents an aliphatic hydrocarbon radical containing from 2 to 18, preferably from 6 to 10, carbon atoms, a cycloaliphatic hydrocarbon radical containing from 4 to 15, preferably from 5 to 10, carbon atoms, an aromatic hydrocarbon radical containing from 6 to 15, preferably from 6 to 13, carbon atoms or an araliphatic hydrocarbon radical containing from 8 to 15, preferably from 8 to 13, carbon atoms. Specific isocyanates include ethylene diisocyanate; 1,4-tetramethylene diisocyanate; 1,6-hexamethylene diisocyanate; 1,12-dodecane diisocyanate; cyclobutane-1,3-diisocyanate; cyclohexane-1,3- and 1,4-diisocyanate and mixtures of such isomers; 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl cyclohexane (German Auslegeschrift No. 1,202,785, U.S. Pat. No. 3,401,190); 2,4- and 2,6-hexahydrotolylene diisocyanate and mixtures of such isomers; hexahydro-1,3- and/or 1,4-phenylene diisocyanate; perhydro-2,4'- and/or -4,4'-diphenyl methane diisocyanate; 1,3- and 1,4-phenylene diisocyanate; 2,4- and 2,6-tolylene diisocyanate and mixtures of such isomers; diphenyl methane-2,4'-and/or -4,4'-diisocyanate; naphthylene-1,5-diisocyanate; and the like. PA1 R represents C.sub.1 -C.sub.8 alkyl or C.sub.1 -C.sub.8 hydroxyalkyl, preferably ethyl or hydroxy ethyl; and PA1 X represents H or methyl, preferably H. PA1 (a) hydroxyl compounds containing more than three OH--groups and having a molecular weight of up to 200, PA1 (b) hydroxyl compounds containing three OH--groups and having a molecular weight of up to 150, PA1 (c) hydroxyl compounds containing two OH--groups and having a molecular weight of up to 80, PA1 a:b=(4,5-6,5):(0,1-1,5), PA1 preferably (5-6):(0,2-1) PA1 a:c=(4,5-6,5):(0,5-1,2), PA1 preferably (5-6):1 PA1 to between 5 and 50%, by weight, preferably to between 15 and 25%, by weight, for the phosphorus-containing condensation products containing at least one hydroxyl group (2): PA1 to between 30 and 70%, by weight, preferably to between 60 and 45%, by weight, for the highly branched polyesters (3): PA1 to between 7 and 40%, by weight, preferably to between 15 and 30%, by weight, for the cyanuric acid derivatives (4): PA1 to between 0 and 10%, by weight, preferably to between 0 and 3%, by weight for water (5): PA1 to between 0 and 25%, by weight preferably to between 0 and 15%, by weight, for the other organic compound containing isocyanate-reactive hydrogen atoms.
According to this proposal, polyesters containing hydroxyl groups and melamine may also be used. However, the polyesters in question are not the highly branched, i.e. polyfunctional, polyesters used in accordance with the present invention, but are instead linear polyesters. The products obtained are thus always rigid.